Green fluorescent proteins has become widely used to study gene expression, in cells and even in whole mammalian organisms. Two-Photon induced fluorescence of Green Fluorescence Protein (GFP) mutant was observed and characterized. Unexpectedly we have found that two-photon cross-section of this GFP mutant is enormously high, several time higher than for wild type GFP. The lifetime and anisotropy decays were measured with one and two photon excitation and analyzed globally. The zero time anisotropy for two photon excitation is large than for one photon excitation by the factor 10/7.